I want to see, I want to know, I want to try, a girl's curiosity is boundless!

In the classroom during a test, Kaede Kasuga was having a hard time concentrating on something.
She had been wondering what the penis on the boy's crotch looked like.
I really wanted to see it, and my desire to do so only grew.
Naturally, I didn't write anything on my answer sheet and got a zero.
Kobayashi, who was sitting behind her, saw her and made fun of her.
In a fit of pique, Kasuga decides to play a game to see who gets the highest score on the next test.
She is momentarily confused by Kobayashi's condition that the loser will do whatever he says, but agrees that if she wins, her wish will come true.
Thus begins Kasuga's intense study to fulfill his wish to see a penis.